Two-shot molded seal integrity indicator, underwater camera, and method

ABSTRACT

A pressure indicator of an underwater camera housing has an indicator support surrounding an opening. An elastomer facing is united with the indicator support. The facing has a free region overlaying the opening. The free region has an inner surface and an outer surface. The free region is deflectable by a relative pressure differential between the inner and outer surfaces. Excessive inward excursion of the free region can be prevented by a backup.

CROSS REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly assigned, U.S. patent application Ser. No.10/037,159, entitled: UNDERWATER ONE-TIME-USE CAMERA HAVING CAMERA FRAMEASSEMBLY RETAINED IN FRONT HOUSING PART AT UNLOADING, filed Dec. 21,2001 in the names of Wayne E. Stiehler and Stephen J. Smith; Ser. No.10/027,291, entitled: DEPRESSURIZED UNDERWATER ONE-TIME-USE CAMERA ,WITH SEAL INTEGRITY INDICATOR AND METHOD, filed Dec. 21, 2001 in thenames of Stephen J. Smith, Craig A. Baker, and Wayne E. Stiehler, Ser.No. 10/027,287, entitled: CAMERA AND UNDERWATER HOUSING HAVING TWO-SHOTMOLDED KNOB SEAT, filed Dec. 21, 2001 in the names of Stephen J. Smith,Craig A. Baker, and Wayne E. Stiehler; Ser. No. 10/027,379, entitled:UNDERWATER CAMERA HOUSING HAVING SEALED PIVOTABLE SHUTTER ACTUATOR ANDMETHOD, filed Dec. 21, 2001 in the names of Stephen J. Smith, Craig A.Baker, and Wayne E. Stiehler; Ser. No. 10/027,284, entitled: UNDERWATERCAMERA HAVING VIEWPORTS BEARING ON VIEWFINDER TUNNEL OF FRAME, filedDec. 21, 2001 in the names of Stephen J. Smith, Wayne E. Stiehler, andCraig A. Baker, Ser. No. 10/027,294, entitled: DUAL ACTION SHUTTERRELEASE WITH THUMBWHEEL BRAKE AND METHODS, filed Dec. 21, 2001 in thenames of Wayne E. Stiehler, Stephen J. Smith, and Craig A. Baker, Ser.No. 29/153,013, entitled: UNDERWATER HOUSING ASSEMBLY, filed Dec. 21,2001 in the names of Stephen J. Smith, Wayne E. Stiehler, Edwin J.Khang, and Jeffrey S. Eng.

BACKGROUND OF THE INVENTION

Underwater cameras, by their nature, are sealed against entry of waterduring use. One-time-use underwater cameras are also usable unsubmerged.While used in air, protection from entry of rain, dust, or the like, mayalso be desirable. Since access is not required for film loading, aone-time-use camera can be sealed air- and water-tightly duringmanufacture. This can be problematic if the one-time-use camera is leftout in the sun. A sealed camera that is left out in the sun can developa high internal pressure. This can cause damage to camera components.The water-tight seal may be lost, without any visible distortion of ahousing or cover.

One solution to this problem is the use of a housing that can berepeatedly opened and closed. This is comparable to the use of areusable camera with a housing or cover that is opened at least everytime film is loaded or use of a separate underwater housing that isinstalled only for underwater use. The housing can be opened asnecessary to prevent overpressurization. This solution is not desirablefor one-time-use underwater cameras, which are intended for casual usewithout restrictive procedures.

Japanese patent publication JP 6-294992A, published Oct. 21, 1994,teaches a waterproof camera case that provides a valve that vents air(or other gas) to relieve excess internal pressure. The valve can alsobe used to evacuate air and add nitrogen at reduced pressure. Thisapproach provides venting to reduce pressure, but adds one or more partsand some complexity. The valve also presents an additional risk ofleakage.

U.S. Pat. No. 4,763,145 teaches a camera that adjusts internal airpressures to permit configuration changes such as moving a lens barrelbetween a wide-angle position and a telephoto position. Space within thecamera for expansion and contraction is provided by a movable piston,elastomer member, or the like. A manual valve is optionally provided forventing.

U.S. Pat. No. 5,870,632 teaches a leakage detector which is used with awaterproof casing of a camera that is pressurized to greater thanatmospheric pressure. The leak detector indicates if pressurization isdecreased due to leakage.

These leakage detectors have the shortcoming of being relatively complexassemblies.

Two shot injection molding is a well-known technique that providesone-piece plastic castings that are made of different materials indifferent regions of the casting. The different materials are united bycodiffusion of adjoining regions of the two different materials. Duringmolding, conditions are selected such that the molecules of the twodifferent regions diffuse together before solidification. The codiffusedzones have interpenetrating polymer networks. (This is also referred toas “molecular entanglement”.)

A variety of two shot molding techniques are known, such as thosedisclosed in U.S. Pat. Nos. 6,066,282; 4,460,534; 6,296,796; and5,737,002. Among these techniques is the use of a hard engineeringplastic for one of the regions and a tougher, but softer material suchas an elastomer, for another region of the casting. EP 0 865 779 A1discloses an orifice coupling that has an internal, soft wiper sealformed by two shot injection molding. The use of two shot molding forthe housing of an underwater one-time-use camera is disclosed in U.S.Pat. No. 5,832,312.

U.S. Pat. No. 4,999,664 teaches an exposure control that respondsautomatically to water pressure when submerged.

It would thus be desirable to provide an improved pressurizationindicator, housing, camera, and method in which the indicator is asimple, two-shot molded structure.

SUMMARY OF THE INVENTION

The invention is defined by the claims. The invention, in its broaderaspects, provides a pressure indicator of an underwater camera housinghas an indicator support surrounding an opening. An elastomer facing isunited with the indicator support. The facing has a free regionoverlaying the opening. The free region has an inner surface and anouter surface. The free region is deflectable by a relative pressuredifferential between the inner and outer surfaces. Excessive inwardexcursion of the free region can be prevented by a backup.

It is an advantageous effect of the invention that an improvedpressurization indicator, housing, camera, and method are provided inwhich the indicator is a simple, two-shot molded structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will be better understood by reference to the followingdescription of an embodiment of the invention taken in conjunction withthe accompanying figures wherein:

FIG. 1 is a front, partially exploded view of an embodiment of theunderwater one-time-use camera.

FIG. 2 is a rear, partially exploded view of an embodiment of theunderwater one-time-use camera.

FIG. 3 is a front, top perspective view of the camera of FIG. 1.

FIG. 4 is a front, bottom perspective view of the camera of FIG. 1.

FIG. 5 is a front, partially exploded view of the camera of FIG. 1showing the front housing part, rear housing part and winding knobseparated from the camera frame assembly.

FIG. 6 is a right, rear perspective view of the front housing part ofthe camera of FIG. 1.

FIG. 7 is a right, front perspective view of the rear housing part ofthe camera of FIG. 1.

FIG. 8 is a perspective view of the camera frame assembly of the cameraof FIG. 1, with the front cover separated from the remainder of thecamera frame assembly. The inside of the front cover is shown.

FIG. 9 is a left, front perspective view of the camera frame assemblyand attached rear cover of the camera of FIG. 1. The front cover andsome other components are deleted for clarity.

FIG. 10 is an exploded view of the camera frame assembly and film unitof the camera of FIG. 1.

FIG. 11 is a perspective view showing the camera of FIG. 1, with thefront housing part, knob, and camera frame assembly detached from therear housing part.

FIG. 12 is a top view of the housing and camera frame assembly of thecamera of FIG. 11, following removal of the winding knob. The rearhousing part and camera frame assembly are shown in plan view. The rearhousing part is detached. The front housing part is shown incross-section.

FIG. 13 is a perspective view of the front housing part and camera frameassembly of FIG. 12. A screwdriver is shown inserted in the screwdriverslot for pivotal movement against the front housing part to open thefilm door for film unit removal.

FIG. 14 is a top view showing the camera frame assembly and fronthousing part of FIG. 13 with the film door opened and the film unitremoved. The front housing part is shown in cross-sectional view and thecamera frame assembly is shown in top plan view.

FIG. 15 is a perspective view of the front housing part and camera frameassembly of FIG. 13 following removal of the camera frame assembly fromthe front housing part.

FIG. 16 is the same view as FIG. 14, but with the camera frame assemblydetached from the front housing part. The front housing part is shown incross-sectional view and the camera frame assembly is shown in top planview. The film door is shown partially closed by the action of theliving hinge.

FIG. 17 is a partial rear perspective view of the camera frame assemblyand front housing part of FIG. 11. The upper left corner is shown.

FIG. 18 is a partial rear perspective view of the camera frame assemblyand front housing part of FIG. 11. The upper right comer is shown.

FIG. 19 is the same view as FIG. 17 of an alternative embodiment of thecamera.

FIG. 20 is the same view as FIG. 18 of the camera of FIG. 19.

FIG. 21 is a partial enlarged perspective view of the camera of FIG. 1showing the winding knob and shutter actuator. For clarity, the facingis not shown.

FIG. 22 is a partial rear perspective view of the front housing part ofthe camera of FIG. 1.

FIG. 23 is a partial enlarged, rear perspective view of the fronthousing part of the camera of FIG. 1.

FIG. 24 is a cross-sectional view of the camera of FIG. 1 takensubstantially along line 24—24 of FIG. 4. The indicator is undeflected.

FIG. 25 is the same view as FIG. 24, but the indicator is deflectedinward.

FIG. 26 is a partial cross-sectional view of the camera of FIG. 1 takensubstantially along line 26—26 of FIG. 2. The knob is in an initialstate.

FIG. 27 is the same view as FIG. 26, but the knob is in a fully traveledstate.

FIG. 28 is a partial semi-diagrammatical cross-section of the sealportion of the knob and the bushing portion of the knob seat of thecamera of FIG. 26. The knob is in the initial state.

FIG. 29 is the same view as FIG. 28, but with the knob in the fullytraveled state of FIG. 27.

FIG. 30 is a partial, enlarged perspective view of the front housingpart of the camera of FIG. 1 showing the knob seat.

FIG. 31 is a partial cross-sectional view of the camera of FIG. 1 takensubstantially along line 31—31 of FIG. 3. The viewfinder tunnel andviewports are shown.

FIG. 32 is a partial cross-sectional view of the camera of FIG. 1 takensubstantially along line 32—32 of FIG. 3.

FIG. 33 is a cut-away perspective view of the camera of FIG. 1 withcomponents deleted for clarity. Shown are part of the front housingpart, the knob, the film unit, part of the frame, and some othercomponents of the camera frame assembly. The shutter is shown in theopen position.

FIG. 34 is a front view corresponding to FIG. 33, but with the fronthousing part and knob deleted from the figure and with the keeperplateshown. The shutter is shown in the open position.

FIG. 35 is a semi-diagrammatical view of the camera of FIG. 1 showingcomponents related to the dual action shutter release and thumbwheelbrake. The shutter is shown in the open position.

FIG. 36 is a partial front-to-back cross-sectional view of the camera ofFIG. 1 with some components deleted for clarity. Shown are a section ofthe front housing part, a section of the facing, the shutter actuator,the high-energy lever, and the shutter release. The shutter actuator isin an initial orientation and the high-energy lever is latched by theshutter release.

FIG. 37 is the same view as FIG. 36, except the shutter actuator is inpivoted orientation and the high-energy lever is released from theshutter release.

FIG. 38 is a partial right-to-left semi-diagrammatical cross-sectionalview of the camera of FIG. 1 with some components deleted for clarity.Shown are the shutter release, the high-energy lever, the shutter, thediaphragm ring, and a pair of biasing springs. The shutter actuator isin an initial orientation and the high-energy lever is latched by theshutter release.

FIG. 39 is the same view as FIG. 38, except that the shutter actuator isin pivoted orientation, the high-energy lever is released from theshutter release, and the shutter is in the open position.

FIG. 40 is a front perspective view of another alternative embodiment ofthe camera. A portion of the facing is cut-away to better show theshutter actuator.

FIG. 41 is a partial cross-sectional view of the camera of FIG. 40 takensubstantially all along line 41—41. The shutter actuator is shown in aninitial orientation.

FIGS. 42-43 are the same view as FIG. 41, except the shutter actuator isshown in the two alternative pivoted orientations.

FIG. 44 is a partial enlargement of the view of FIG. 35, of amodification of the camera, in which the sprag is tooth-shaped and thethumbwheel has a rack. The shutter release is in the downward pivotedconfiguration.

FIG. 45 is the same view as FIG. 44, but the shutter release is shown inthe unpivoted configuration.

FIG. 46 is the same view as FIG. 44, but the shutter release is in theupward pivoted configuration.

FIG. 47 is a front perspective view of an alternative camera includingthe frame unit of the camera of FIG. 1. The button of the shutterrelease is shown.

FIG. 48 is a semi-diagrammatical perspective view of an incompletecamera like the camera of FIG. 1 and assembly equipment. The enclosureis shown with the hatch open.

FIG. 49 is the same view as FIG. 48, but the hatch is shown closed, andpartial cut-away. The winding knob is not yet seated.

FIG. 50 is the same view as FIG. 49, after seating of the winding knob.

FIG. 51 is the same view as FIG. 25 of another embodiment of the camera.The indicator is deflected inward.

DETAILED DESCRIPTION OF THE INVENTION

The invention is generally described herein in reference to particularembodiments in which the one-time-use camera uses photographic film andcombines various features. The invention is not limited to suchembodiments. It will be apparent to those of skill in the art thatfeatures, that various of the features disclosed can be included orexcluded, within the limits defined by the claims and the requirementsof a particular use.

For example, the camera can capture images electronically rather thanusing photographic film or can be a film-electronic hybrid that usesboth. The camera can capture video in addition to or instead of stillimages. The camera can be reusable rather than one-time-use. The housingcan be used other kinds of equipment, such as a rangefinder or flashunit.

Referring now to FIGS. 1-10, the camera 10 has a pressure housing 12 anda frame assembly 14 disposed within the housing 12. One or more usercontrols 16 extend from the outside of the housing 12 to the cameraframe assembly 14. The camera frame assembly 14 holds a film unit 18that stores captured images. In the embodiment shown in FIG. 1, the filmunit 18 is a photographic film cartridge 18a and the user controls 16are a shutter actuator 20 and a winding knob 22 that is wound to advancethe photographic film between exposures. In the photographic film-typeone-time-use cameras discussed herein, the film unit 18 is a filmcartridge 18 a, which has a canister 18 b and a spool 18 c internal tothe canister 18 b. A filmstrip 18 d is joined to the spool 18 c and,prior to use extends out of the canister to a prewound film roll 18 e.

The housing 12 has two or more parts joined together. In the embodimentsshown in the figures, the housing 12 has a first or front housing part28, having a back opening 29, and a second or rear housing part 30 thatare sealed together during use. In these embodiments, the housing 12divides vertically between the front and rear housing parts 28,30. Itwill be understood that the housing parts 28,30 can be modified todivide the housing 12 in other ways, such as horizontally, and thehousing parts 28,30 can themselves be divisible, if desired. The housing12 has an inner surface 32 and an outer surface 34 and a passage 36extending between the surfaces 32,34 for winding knob 22.

The housing 12 has a shell 24 and a facing 26 that is united with theshell 24, that is, in each housing part, the shell 24 and facing 26 areor act like a one-piece structure. The shell 24 is included in bothfront and rear housing parts 28,30. The facing 26 can be included inboth front and rear housing parts 28,30; but in the embodimentsdisclosed herein, is limited to the front housing part 28.

The facing 26 can cover the entire outer surface 34 of the housing partor parts, or can be limited to regions of the housing 12 where thefacing 26 provides a particular function. Alternatively, those and otherregions of the housing 12 can be covered, as desired, for artisticeffects.

The facing 26 is relatively soft and the shell 24 is relatively hard.The soft facing 26 can be used to provide a seal between housing parts28,30. A convenient seal can be provided by configuring the shell 24 inone of the housing parts to have a continuous tongue 38 extending aroundthe edge and in the other housing 12 part to have a matching groove orrabbet 40 configured to overlap the tongue 38. When assembled, thefacing 26 is compressed between the tongue 38 and rabbet or groove 40.(This is best seen in FIG. 32) The compressed section of facing takesthe place of an O-ring or washer.

The uniting of shell 24 and facing 26 can be provided by bonding one tothe other by adhesive or the like. It is preferred that the housing 12be prepared by a technique commonly referred to as “two shot” or “twopack” injection molding. In two-shot molding, a set of die members (notshown) are initially positioned to define a mold having a first cavitythat molds one of two sections of the part to be produced. The cavity isfilled with a first moldable material during a first injection shot. Oneor more of the die members is then moved to define a second cavity thatholds the molded product of the first moldable material and is largerthan the first cavity. A second injection shot is then made with asecond moldable material. The temperature of the mold is maintained suchthat the first moldable material will melt along the interface with thesecond moldable material during the molding process, such that the firstmoldable material maintains its integrity, only being effected along theinterface and not washing out as the second moldable material is shotinto the mold. The moldable materials are selected such that the twoshots of material diffuse together at the interface, before hardening.This effect, described as: codiffusion or molecular entanglement,results in an interface region that is comparable in character to a bulkinterpenetrating polymer network.

A housing part produced by two shot molding, is a one-piece plasticcasting that has an engineering plastic shell 24 and a softer,preferably elastomer facing 26. The term “engineering plastic” and“elastomer” are each used herein in an ordinary technical sense. Forexample, a definition is provided in the Concise Encyclopedia of PolymerScience and Engineering, J. I. Kroschwitz, ed., John Wiley & Sons, NewYork, 1990, at page 326:

“Engineering plastics are thermoplastics that maintain dimensionalstability and most mechanical properties above 100 degrees C. and below0 degrees C. This definition encompasses plastics that can be formedinto functional parts that can bear loads and withstand abuse intemperature environments commonly experienced by the traditionalengineering materials: wood, metals, glass, and ceramics. Generic resinsfalling within the scope of this definition include acetals, polyamides(nylons), polyimides, polyetherimides, polyesters, polycarbonates,polyethers, polysulfide polymers, polysulfones, blends or alloys of theforegoing resins, and some examples from other resins types”.

The same source describes elastomers at page 295:

“Elastomers are derived from natural rubber and synthetic polymers withrubberlike properties. They exhibit both long-range deformability onapplication of stress and complete recovery on removal.”

Examples of specific materials for the shell and facing arepolycarbonate/polyurethane or polystyrene/styrene-butadiene.

The shell 24 can be textured by the mold surface to provide a bettergrip for the user. For clarity, texturing of the surface of shell 24 isonly illustrated in some of the figures.

The frame assembly 14 has most of the features of a completedone-time-use camera 10. Exceptions are one or more user controls 16,which are modified so as to the usable from outside the housing 12 and,in a particular embodiment discussed below, retention features that holdthe camera frame assembly 14 in the front housing part 28.

The camera frame assembly 14 has a front cover 42 and a rear cover 44.The covers 42,44 are joined together over a frame unit 46. The frameunit 46 and rear cover 44 define a film space 48 including a pair offilm chambers 50,52 and an exposure chamber 54 between the film chambers50,52. The film space 48 is light-tight. It is convenient if lightblocking is provided by the frame unit 46 and the rear cover 44. In thiscase, it is unnecessary for the front cover 42 to provide a lightblocking function.

It will be understood, that the various features disclosed herein in theused in combination is not disclosed and can be modified in a mannerknown to one of skill in the art. For example, a housing 12 andrespective cover of the camera frame assembly 14 could be combined in asingle part.

The frame unit 46 has a frame 56, which, preferably, is a single plasticcasting. The frame 56 includes the film chambers 50,52 and exposurechamber 54. Extending forward from the exposure chamber 54 is a baffle58. At the forward end of the baffle 58 is a shutter 60 and a lensassembly 62. The lens assembly 62 includes one or more plastic or glasslens elements 64, a lens holder 66, and a diaphragm ring 67. The shutter60 shown is a single leaf impact-type shutter. As with other components,the shutter 60 can be varied.

The frame unit 46 has a metering lever 68 and a high-energy lever 70,which are operated by cams 72,74 of a sprocket-cam unit 76. One or morebiasing springs 78 hold the levers 68,70 against the respective cams72,74, as needed. The sprocket-cam unit 76 also has a sprocket 80 thatextends into the film space 48. Perforations 82 of the filmstrip 18 dengage the sprocket 80. The sprocket 80 rotates when the film 18 d isadvanced by the rotation of a thumbwheel 84.

The sprocket-cam unit 76 has an axle 77 that fits in holes in the frame56 and in a keeperplate 88 mounted to the upper end of the frame 56. Thehigh-energy lever 70 and the metering lever 68 rotate on posts 90 of theframe 56. A counterwheel 92 is driven by the sprocket-cam unit 76 andcounts film exposures. The counterwheel 92 is also mounted on one of theposts 90.

It is convenient to incorporate additional features in the keeperplate88. In the embodiments shown, the keeperplate 88 is transparent plasticand includes: a shutter release 94, a retainer 96 that holds thecounterwheel 92 in place, a viewfinder lens element 98 and an upper wall100 of the viewfinder 102, and a counterwheel lens 104. A leg 105 of thekeeperplate 88 attaches to a holdfast 107 of the frame 56 to hold thekeeperplate 88 in position.

The thumbwheel 84 is held between the keeperplate 88 and frame 56 andextends through an opening 106 in the frame 56 into the film cartridgechamber 52. A fitting 109 (shown in FIG. 35) of the thumbwheel 84mechanically engages the internal spool 18 c of the film cartridge 18a.The covers 42,44 have an opening 108 that overlies a socket 110 of thethumbwheel 84. The socket 110 and the end of a shaft of the winding knob22 engage, causing the thumbwheel 84 to rotate when the knob 22 iswound.

Referring to FIG. 11, the thumbwheel 84 is preferably subject to theaction of a one-way clutch 112. In the embodiment illustrated, theone-way clutch 112 is an anti-backup lever 112 a that engages externalteeth 115 of the thumbwheel 84. The anti-backup lever 112 a is providedas a resilient arm formed as a part of the rear cover 44. Otheranti-backup levers and other types of one-way clutches can also be used.

The thumbwheel 84, in the embodiments shown, is exposed on the outsideof the camera frame assembly 14, as is a shutter button 114. Thethumbwheel 84 and/or the shutter button 114 can, alternatively, beenclosed by the covers 42,44, except over the socket 110. In anembodiment discussed below, the shutter release 94 includes a shutterbutton 114, in the form of a raised area that extends upward relative tothe remainder of the shutter release 94. The shutter button 114 can beexposed, but is not externally accessible in the illustrated embodimentsof underwater one-time-use cameras. The front cover 42 has an opening116 in the vicinity of the shutter release 94 for a shutter actuator 20.One or more locating features 118 can be provided on the covers 42,44and housing parts to help guide and maintain placement of the housingparts 28,30.

The camera frame assembly 14 is assembled in the same manner as withother one-time-use cameras 10. Components are mounted to the frame 56.The frame unit 46 is then placed in the front cover 42, a film unit 18is loaded in the camera 10, and the back cover 44 is attached. The filmroll 18 e can be formed prior to film loading or after, by winding film18 d out of the canister 18 using an exposed end of a second spool 120or other winding mechanism.

The completed camera frame assembly 14 is placed in the front housingpart 28 and the rear housing part 30 is attached to the front housingpart 28. The winding knob 22 is then inserted through the passage 36 andinto engagement with the socket 110 of the thumbwheel 84. The windingknob 22 is held in place on the housing 12 by a catch 122. The catch 122permits the winding knob 22 to be released from the housing 12 andreattached without damage, one or more times. This functionality isintended for recycling, rather than during camera use.

Referring now to FIGS. 48-50, in a preferred embodiment, the partiallyassembled camera 10 is a placed within a nest 124 in a gas tightenclosure 126, after the housing parts 28,30 are fit together and beforethe knob 22 is attached. A hatch 128 of the enclosure 126 is closed,sealing the interior of the enclosure 126. The enclosure 126 is thenevacuated by a vacuum source 130 to a pressure below atmosphericpressure. If desired, the initial atmosphere can be exchanged withnitrogen or some other atmosphere.

The enclosure 126 has a placement device 132 located in alignment withthe passage 36 through the housing 12, when the housing 12 is in thenest 124. The placement device 132 holds the knob 22 and moves linearlyso as to install the knob 22 in the passage 36. After the interior ofthe enclosure 126 has reached a desired pressure and/or atmosphericcomposition, the knob 22 is pushed into place in the passage 36 of thehousing 12. The interior of the enclosure 126 is then repressurized, thehatch 128 is opened, and the completed camera 10 is removed. The cameraremains sealed without venting or leakage until usage is completed andthe camera is submitted for photofinishing.

It has been determined that sealing, in the camera, air at a reducedpressure is practical for use of the camera 10. The atmosphere sealedwithin the camera 10, before evacuation, is initially at normal orreduced humidity and at room temperature. In a particular embodiment,the camera 10 is intended to withstand internal temperatures of 120degrees F. (49 degrees C.). It is preferred for this embodiment that thecamera 10 be sealed with an internal pressure of 8.6 psi (59 Kpa). Thisyields a final pressure of 14.7 psi (101 Kpa) when heated to 120 degreesF. (49 degrees C.).

It is a desirable that the camera 10 have a pressurization/sealintegrity indicator that provides a constant indication to the user,that the camera 10 remains sealed and, thus, available for underwateruse. Such indicators are known in the art. Referring now particularly toFIGS. 4 and 23-25, in a preferred embodiment, the seal integrityindicator 134 is provided by a free region 136 of the elastomer facing26 that covers 42,44 an opening or passage 138 in one of the housingparts 28,30. Surrounding the free region 136 is a supported region 139that is united with a border portion or indicator support 140 of theshell 24 surrounding the opening 138. The free region 136 has an outersurface 135 that is exposed to the external environment and an innersurface 137 that is exposed to the interior of the housing 12. The outersurface 135 can be directly exposed to the outside environment, as shownin FIG. 4. The free region 136 can, alternatively, be partially shieldedby an extension (not shown) of the shell that protects against intrusionby foreign objects. The latter is not preferred, since it makesdifficult or precludes automated or manual detection of seal integrityby touching the free region 136.

In the embodiments shown, the free region 136 is a section of theelastomer facing united with the outside 141 of the shell 24. The freeregion 136 can instead be provided on the inside 143 of the shell 24.

It is highly preferred that the camera 10 is depressurized sufficientlyto deflect the free region 136 inward when the camera 10 is unsubmergedat moderate temperature, 18 degrees C. to 24 degrees C., and moderatealtitude, at sea level or below 930 meters above sea level. Under suchconditions, the user can check the integrity of the camera seal, whileunsubmerged, by looking at or touching the indicator 134. The sealintegrity indicator 134 can also be checked during camera assembly usinga detector (not illustrated), such as a mechanical finger or opticalsensor, or the like. Cameras having an undeflected or incompletelydeflected free region 136 can be culled during assembly or otherwisebefore underwater use. Under high temperatures up to 120 degrees F., theinternal pressure can be higher than external pressure, causing the freeregion to deflect outwards (shown in FIG. 25 by dashed lines).

The seal integrity indicator 134 has a backup 142 that is located,within the housing 12, interior to and overlapping the opening 138. Thefree region 136 flexes inwardly if a sufficient pressure differential isprovided between the interior of the housing 12 and the externalenvironment. The backup 142 is spaced from the free region 136 so as toallow some inward excursion of the free region 136, but to limit inwardexcursion of the free region 136 under higher pressures. This protectsthe free region 136 against excessive excursion during use underwater,which could lead to failure and water leakage.

The backup 142 is sufficiently rigid to resist the compressive forcestransferred by the free region 136 without distorting. The backup 142has a primary surface 144 that faces the free region 136. The primarysurface 144 is shaped so as to support all or a large area of the freeregion 136, when the free region 136 is maximally distended. Aconvenient shape for the primary surface 144 is flat, since this shapeis easy to mold and most of the free region 136 is supported at maximaldistension. Maximal distension is the extent of distension at apredetermined test depth that meets or exceeds a recommended maximumdepth of use. The camera is functional at test depth. Below test depthphotographic functionality degrades and eventually ceases. Below testdepth is a crush depth, at which the camera catastrophically fails.

The backup 142 can be part of the shell 24 or part of the camera frameassembly 14. If the backup 142 is part of the camera frame assembly 14,it is preferred that the backup 142 is part of the frame 56 rather thanone of the covers 42,44. In the embodiment shown in FIG. 51, the backup142 is a portion of the frame 56. In the embodiment other figures, theopening 138 is in the front housing part 28 and a backup 142 is aportion of the rear housing part 30.

If the camera 10 is depressurized to an internal pressure of 8.6 psi (59Kpa), a convenient size for the opening 138 is 9 mm and a convenientdepth from the opening 138 in the shell 24 to the backup 142 is 3 mm. Asuitable elastomer thickness at the free region 136 is easily selectedby trial and error. In preferred embodiments of the invention, the sealindicator 134 does not function as a pressure gauge, since the interiorof the camera 10 is evacuated and atmospheric pressure at sea levelcauses the seal indicator 134 to dish in. In other embodiments, the sealindicator 134 functions as a rough pressure gauge. The opening 138 canbe sized and/or stretchiness of the free region 136 can be adjusted todeflect only at a desired water pressure. The interior of the camera 10can be left at atmospheric pressure, evacuated, or pressurized tofurther vary the result. Multiple seal indicators 134, each of whichdish in at a different depth, can be provided on a camera 10 or otherhousing 12. Suitable dimensions and characteristics can be easilydetermined by trial and error. For example, a range of different sizeholes can be covered with free regions 136 of uniform material andthickness and depths for dishing in of each indicator 134 can then bedetermined experimentally.

Referring now particularly to FIGS. 2, 5, 18, and 26-30, the windingknob 22 has a handle 146 at one end that is knurled or otherwise shapedso as to be gripped by the user. Extending downward from the handle 146is the shaft 148 that mates with the socket 110 formed in the thumbwheel84.

The passage 36 extends through an outwardly extending knob seat 150 onthe top of the first housing part 28. The knob seat 150 includes aregion of the shell 24 that defines an outer sidewall 152 of the knobseat 150. The outer sidewall 152 extends around the knob seat 150, withone or more interruptions. At the interruptions, a channel 154 extendsupward along the knob seat 150 away from the interior of the housing.The knob seat 150 has an inner sidewall or bushing portion 156 thatsurrounds the passage 36. The bushing portion 156 is formed by thefacing 26. The facing 26 also occupies the channels 154. Most of theouter sidewall 152 is thus hard and the inner sidewall is soft. Thefront housing part 28 has facing 26 over the shell 24 adjoining theouter sidewall 152. This feature and the facing 26 in the channels areartifacts of molding and can be varied by use of more complex molds.

The lower surface 158 of the handle 146 of the knob 22 is shaped so asto be able to register the outer edge 160 of the knob seat 150 and ispreferably undercut so as to define an annular slot 162 matched to theshape of the knob seat outer edge 160. The bushing portion 156 is angledinward toward the common axis 164 of the passage 36 and winding knob 22and toward the interior of the housing 12. The knob 22 has a sealportion 166 having a complementary shape. The seal portion 166 is partof the shaft 148 that borders and extends downward from the slot 162.The seal portion 166 is, thus, shaped like a truncated cone. Below theseal portion 166 and bushing portion 156, the knob 22 and knob seat 150,respectively, have wall portions 168,170 that engage slideably. The wallportion 168 of the knob seat 150 is cylindrical. The wall portion 170 ofthe knob 22 is illustrated as being shaped like a discontinuouscylinder, but can be continuous, if desired.

Below the wall portion 168 the knob 22 is divided into an engagementportion 172 that mates with the socket 110 of the thumbwheel 84 and anattachment portion 174 that releaseably joins the knob 22 to a joiningportion 176 of the front housing part 28. The attachment portion 174 andjoining portion 176 together comprise the earlier discussed catch 122.

The engagement portion 172 is shaped so as to mesh with the socket 110of the thumbwheel 84 and can be solid or, as shown, in the form of apair of opposed flanges 178. The flanges 178 act as an overrunningclutch, by deflecting under excessive pressure and then recoveringelastically. This prevents excessive winding from damaging thecomponents. With a solid engagement portion 172, the socket 110 of thethumbwheel 84 can be modified to provide a similar flexible member andover-running clutch function. It is preferred that the attachmentportion 174 and joining portion 176 of the catch 122 resilientlyinterlock and that one or both of the attachment portion 174 and joiningportion 176 be able to resiliently deflect to permit easy seating anddetachment of the knob 22 without risk of damage to the knob 22 orhousing part. In the embodiment shown in the FIG.s, the attachmentportion 174 is a pair of opposed hooks 174 a,174 band the joiningportion 176 is a pair of opposed ledges 176 a,176 b that are portions ofthe inner surface 32 of shell 24. The ledges 176 a,176 b shown in FIGS.26-27 protrude toward the interior of the housing 12 relative to therest of the inner surface 32. The ledges 176 a,176 b can alternativelybe coplanar with or recessed relative to the inner surface 32, dependingupon shell 24 thickness and the length of the shaft 148 of the knob 22.The hooks 174 a,174 b each extend downward and then hook or recurveoutwardly. The hooks 174 a,174 b engage the inner surface 32 of theshell 24 when the knob 22 is initially inserted in the housing 12. Thebottom rim 180 of the passage 36 is angled inward toward axis 164. Thehooks 174 a,174 b are flexible and the angled bottom rim 180 bends thehooks 174 a, 174 b to ease the effort required for seating the knob 22.The attachment portion 174 and joining portion 176 can be varied. Forexample, the joining portion 176 can be in the form of hooks and theattachment portion 174 in the form of ledges or recesses. Hooks can bereplaced by spring-loaded detents or other like structures.

The knob 22 is seated, during assembly, by pressing the knob 22 into thepassage 36 until the tangs of the hooks 174 a,174 b clear the bottom ofthe passage 36 and engage the inside of the shell 24. The bushingportion 156 is slightly or moderately compressed by this procedure,resulting in a gas-tight seal. In this initial state, the outer edge 160of the knob seat 150 does not contact the base wall 182 of the slot 162in the handle 146 of the knob 22.

Space is provided between the knob 22 and both the socket 110 of thethumbwheel 84 and the outer edge 160 of the knob seat 150, to allowfurther movement of the knob 22 into the passage 36. This occurs as aresult of water pressure during submerged use. Contraction as a resultof cooling during submerged use can also contribute to this movement ofthe knob 22 along the passage 36 toward the interior of the housing 12.When the camera 10 is submerged, the knob 22 is pushed further into thepassage 36. This drives the seal portion 166 deeper along the wall ofthe bushing portion 156, increasing or at least maintaining the area ofcontact between the two portions in all positions of the knob 22 in thepassage 36 from a normal pressure or minimum position through a maximumpressure position. Since the bushing portion 156 is elastomer, theinward movement of the knob 22 is resisted by internal resilience of thebushing portion. For the same reason, the bushing portion 156 tightlygrips the seal portion 166. As pressure increases, the knob 22 continuesinto the passage 36 until reaching a fully traveled state in the maximumpressure position. In the minimum position, the hooks 174 hold the knob22 in position against the resilience of the bushing portion 156. Thisresilience must be overcome in initially seating the knob. In themaximum pressure position, the bushing portion is compressed by waterpressure until the outer edge 160 of the knob seat 150 bears against thebase wall 182 of the slot 162 of the handle 146. The hooks are locatedinterior to the inner surface 32 of the housing 12. The housing 12 canhave a partially or fully encircling reinforcement wheel 159 that is asection of the shell 24 and helps bear the load of the knob handle 146when the knob 146 is in the maximum pressure position. The reinforcementwheel 159 can be split between the two housing parts 28,30, as shown inFIGS. 1-2.

The shell 24 has a support surface 184 that adjoins the bushing portion156. The support surface 184 is L-shaped and faces outward and towardthe axis 164 of the passage 36. The inward travel of the knob 22 in thepassage 36 tends to drive the bushing portion 156 back against thesupport surface 184, compressing the bushing portion 156.

It is preferred that the bushing portion 156 and seal portion 166 havecomplementary shaped contact surfaces 155,157 and that these surfacesare angled outward relative to the axis of the passage and the interiorof the housing. This ensures a good grip between the bushing portion 156and seal portion 166 in the different positions of the knob 22 in thepassage 36.

The knob seat 150 can be modified to accommodate other rotary usercontrols 16. Such user controls 16 have seal portions 166 and bushingportions 156 like those above-described. The knob seat 150 can bemodified for linearly movable controls if a separate feature, such as aflexible bag, is added to provide water-tightness and/or air-tightness.With such a linearly movable control, FIGS. 26-27 would represent atransverse cross-section. Due to the added complexity, a linearlymovable control is not preferred.

Referring now to FIGS. 6-10, 15, and 31-32, the camera 10 has aviewfinder 102 that includes portions of the housing 12 and of the frameunit 46. The housing 12 has a pair of opposed viewports 186,188. Eachviewport 186,188 has a view area 190 and a structural rim 192surrounding the view area 190. The structural rims 192 of the twoviewports 186,188 bear on opposite ends of a viewfinder tunnel 194 thatis a part of the frame 56.

The tunnel 194 is formed by a set of parallel sidewalls 196 that arepart of the frame 56. The sidewalls 196 have longest dimensionsextending from front to back of the camera 10. The sidewalls 196 canhave a set of inwardly directed flanges 198 positioned to block lightflare. The sidewalls 196 have front and rear outward edges 200,202 thatare closest to respective viewports 186,188.

The front and rear covers 42,44 each have a viewport opening 191,193, bymeans of which the respective viewports 186,188 and outward edges200,202 come into contact. The sidewalls 196 can extend out one or bothopenings 191,193. Likewise, one or both viewports 186,188 can extendinto a respective opening 191,193.

Front and rear stub walls 204,206 (best seen in FIGS. 10 and 32,respectively) join the sidewalls 196 together at the bottom. Between thestub walls 204,206, the bottom of the viewfinder 102 is provided by aportion of the baffle 58. At the top, the tunnel 194 is open. Thekeeperplate 88 has a portion that acts as a tunnel top 208 and anotherportion that provides the viewfinder lens element 98. The tunnel upperwall 100 is offset inwardly from the outward edges 200,202.

When the camera 10 is unsubmerged, the outward edges 200,202 are locatedin close proximity to the structural rims 192 of the respectiveviewports 186,188. When the camera 10 is submerged, the housing partsare squeezed toward each other and the compressive load on the viewports186,188 is transferred directly to the viewfinder tunnel 194, throughload-bearing contact of the structural rims 192 and respective outwardedges 200,202. In other regions of the camera 10, the compressive forceis transmitted from the housing 12 through the respective covers 42,44to specific sections of the frame 56. Compressive force is primarilytransmitted through the front cover 42 to reinforcements 208 located onboth of the film chambers 50,52 of the frame 56. These sections of theframe 56 are strong and quite rigid as a result of the shapes requiredfor the film chambers 50,52. Compressive force transmitted through therear cover 44 is primarily born by the light lock 210,212 of the frame56 and rear cover 44. The light lock 210,212 is formed at the margins ofthe film chambers 50,52 and the exposure chamber 54. The light lock210,212 provides a relatively large area of contact.

The front and rear covers 44 of the camera frame assembly 14 do notreceive the compressive load transmitted by the viewports 186,188 whenthe camera 10 is submerged. In the preferred embodiment shown in thefigures, the front and rear covers 44 are offset from the respectiveviewports 186,188 and do not make contact with the housing 12 in thevicinity of the viewports 186,188. This protects the covers 42,44 frombending stresses, when submerged, which could distort overall shape ofone or both covers 42,44 and possibly interfere with camera function. Italso allows the covers 42,44 to be unreinforced in the area of theviewfinder 102, since the load is not borne by the covers 42,44 in thatarea.

Stronger structure must be provided at the viewfinder tunnel 194. Thisis not an undesirable feature, since the frame 56 is commonly reusedwhen a one-time-use camera 10 is recycled and good structural strengthof the frame 56 helps prevent damage during that recycling. Thecompressive force on reinforcements 208 and light lock 210,212 isunlikely to distort the covers 42,44, since the force is balanced by abearing structure at each corner of the camera 10 and those structuresare relatively near edges of the covers 42,44 and not near largeopenings. At the viewfinder 102, compressive force that would be morelikely to distort the covers 42,44 is born, instead by the tunnel 194 ofthe frame 56.

One or both of the viewports 186,188 can have an optical power. Theother viewports 186,188 or both viewports 186,188 can, alternatively,lack optical power. If the viewport does not have an optical power, thenthe viewfinder 102 includes the separate lens element 98 located inclose proximity to the respective viewport 186 or 188. A separate lenselement can also be used with a viewport 186,188 that has an opticalpower.

Referring now particularly to FIGS. 3, 15, 21-22, and 33-43, in aparticular embodiment, the actuator 20 is attached to the front housingpart 28. In the embodiments shown, the actuator 20 is positioned to acton a shutter release. For this reason the actuator 20 is generallyreferred to herein as a “shutter actuator 20”. It will be understoodthat the actuator can act on any of a wide variety of effectors withinthe housing, such as pressure or mechanical switches for a variety ofcamera functions.

The shutter actuator 20 has an outer member 214, an inner member 216,and a torsion bar 218 between the members 214,216. The outer member 214extends outward from the torsion bar 218, beyond the front surface 220of the front housing part 28. The inner member 216 extends inward beyondthe back surface 222 of the front housing part 28 and through opening116 in the front cover 42 of the camera frame assembly 14.

The torsion bar 218 bridges an opening in the front housing part 28,dividing the opening into upper and lower subopenings 224,226. In theembodiments shown, the torsion bar 218 is aligned with the front surface220 of the front housing part 28. The outer and the inner members214,216 of the shutter actuator 20 extend outward and inwardrespectively from the torsion bar 218.

External portions of the shutter actuator 20 are fully covered by thefacing 26. In other words, the facing 26 overlies the outer member 214and outside surface of the torsion bar 218. For this purpose, it ispreferred that the facing 26 is made of elastomer codiffused with theshell 24. The facing 26 bridges over the upper and lower subopenings224,226 of the front housing part 28. The housing 12 is, thus, sealed atthe shutter actuator 20. The portion of the facing 26 overlying theouter member 214 of the shutter actuator 20 can have ridges or otherrelief to reduce the risk of slippage of the user's finger from theshutter actuator 20 while underwater or in other rough usage.

It is highly preferred that the shutter actuator 20 is formed in aone-piece with the facing 26 and shell 24 of the front housing part 28.In that case, the shutter actuator 20 is engineering plastic formed inthe first shot of the two-shot molding along with the shell 24. It isalso highly preferred that the facing 26 is formed over the shell 24 andshutter actuator 20 during the second shot of the two-shot moldingprocess.

The shutter actuator 20 is movable relative to the front housing part 28between an initial orientation and a pivoted orientation. The torsionbar 218 is twisted about a longitudinal axis (this axis is not indicatedin the figures) transverse to the subopenings 224,226 in the fronthousing part 28, when the shutter actuator 20 is moved from the initialorientation to the pivoted orientation. The internal resilience of thetorsion bar 218 biases the shutter actuator 20 toward the initialorientation. (The torsion bar 218 is relaxed in the initial orientationand tensioned in the pivoted orientation.) The elastomer of the facing26 covers and, optionally, extends into the upper and lower subopenings224,226 forming a pair of resilient corner pads 228,230. When theshutter actuator 20 is deflected from the initial orientation to thepivoted orientation, the comer pads 228,230 are distorted and, byinternal resilience, provide an additional biasing of the shutteractuator 20 toward the initial orientation.

It is preferred that equal biasing of the shutter actuator 20 beprovided by the upper and lower comer pads 228,230. The biasing providedby the comer pads 228,230 is a function of material, size, and shape.For simplicity, it is preferred that the comer pads 228,230 are each ofthe same material and are the same size and shape. In that case, theresilience of the two comer pads 228,230 tends to be balanced. If theresilience is not balanced, then the shutter actuator 20 is moreresistant to pivoting in one direction than the other. This interfereswith ease of use and, depending upon the direction of maximumresistance, can result in unintended exposures.

It is highly preferred that the biasing of the shutter actuator 20toward the initial orientation is mostly provided by the torsion bar 218rather than the comer pads 228,230. The change in resilience of thetorsion bar 218, with depth, is less than the change in resilience ofthe comer pads 228,230. The comer pads 228,230 tend to “stiffen”, thatis become more resistant to deflection, when distended inward by waterpressure. The effect of such stiffening on the shutter actuator 20 canbe minimized by limiting the biasing of the shutter actuator 20 by thecomer pads 228,230 to a small percentage of the total biasing of theshutter actuator 20. The use of comer pads 228,230 that provide a smallpercentage of the total resilience also reduces the effect of anyinadvertent inequalities in the resilience of the upper and lower comerpads 228,230 due to irregularities in the molding process or the like.

The inner member 216 is positioned within the camera frame assembly 14such that the pivoting movement of the shutter actuator 20 pushes theinner member 216 against the shutter release 94. This causes the shutterrelease 94 to pivot upward and releases the latching of the high-energylever 70. The high-energy lever 70 swings under the action of a biasingspring 78. The high-energy lever 70 strikes an end of the shutter 60,which swings open for an exposure of a film frame 56. The shutter 60then swings closed as a result of the biasing of a shutter biasingspring 78. The film 18 d is wound forward to the next frame 56 and thecycle is repeated. An example of a suitable mechanism that providesthese functions is described below. Alternative shutter mechanisms canbe used, with the limitation that the triggering movement of the innermember 216 of the shutter actuator 20 is in an upward direction.

The outer member 214 of the shutter actuator 20, which extends outwardfrom the front surface 220 of the front housing part 28, has two opposedcounterbalance surfaces 232,234. One counterbalance surface 232 facesupward the other counterbalance surface 234 faces downward. A shutteractuation is provided by pressing the upper counterbalance surface 232of the outer member 214 in a downward direction. Since bothcounterbalance surfaces 232,234 are exposed to the external environmentin both the initial orientation and the pivoted orientation, waterpressure on the outer member 214 does not change when the shutteractuator 20 is tripped. The facing 26 of the camera 10 provides somecorner padding against rough treatment. For additional protection, aguard 236 can be provided on the front housing part 28 so as to helpprotect the outer member 214 of the shutter actuator 20. The guard 236can be shaped so as to extend beyond the outer member 214 in alldirections and protect the outer member 214 from impact. Thecounterbalance surfaces 232,234 are continuously spaced from the guard236 to ensure equal water pressure on both counterbalance surfaces232,234.

Referring now to FIGS. 36-39, when the shutter actuator 20 is pusheddown the shutter release 94 is pivoted in an upward direction away fromthe interior of the camera frame assembly 14. This causes the latchedhigh-energy lever 70 to be released, striking the shutter 60 andexposing a film frame 56. The shutter release 94 is joined to a mainportion of the keeperplate 88 by a living hinge 237.

In a particular embodiment of the invention shown in FIG. 40, a camera10 a has a shutter actuator 20 that pivots in and out relative to afront housing part 28. In this embodiment, the torsion bar 218 is joinedto two opposed outer members 214 and two inner members 216 extend inwardfrom respective outer members 214. The facing covers and contacts theouter members 214 and subopenings 224,226. When pressed by the user, theshutter actuator 20 pivots from an initial orientation, shown in FIG.41, to either of two pivoted orientations, shown in FIGS. 42-43. Ashutter release 94 is contacted by the shutter actuator 20 in thepivoted orientations. The shutter release 94 shown in FIGS. 41-43 is apair of contact pads for an electronic shutter (not illustrated). Othershutter releases can be provided in a similar manner.

Referring now particularly to FIGS. 33-39 and 44-47, in a particularembodiment of the invention, the shutter release 94 is pivotable in boththe upward direction just described and in an opposite, downwarddirection toward the interior of the camera frame assembly 14. In thisembodiment, a sprag 238 is joined to the shutter release 94. The sprag238 bears against the thumbwheel 84 when the shutter release 94 is ineither the upward released position or the downward released position.

The shutter release 94 is released in an upward direction when used in acamera having shutter actuator 20. The shutter release 94 can also bereleased in a downward direction, during manufacturing, prior toinstallation of covers 42,44, or if used in a non-underwater camera 10 b(shown in FIG. 47) having features like the camera shown in FIG. 1, butno housing and an exposed shutterbutton 114.

The sprag 238 is a cut-out section that is pivotably joined to theshutter release 94 by a living hinge 239. The sprag 238 can pivotindependent of the shutter release 94. The sprag 238, as a result of theinternal biasing of the living hinge 239, is initially in an unpivotedconfiguration, in which the sprag 238 is aligned with the shutterrelease 94. In the unpivoted configuration, the sprag 238 does not bearon the thumbwheel 84. The sprag 238 is in the unpivoted configurationwhen the shutter release 94 is in a neutral or ready position and thehigh-energy lever 70 is latched, or, alternatively, the high-energylever 70 has discharged, but the film frame 56 exposed has not beenadvanced.

When the shutter release 94 is moved into the downward releasedposition, the sprag 238 pivots with the shutter release 94 until adownwardly extending tab 240 of the sprag contacts an upper surface 245of the thumbwheel 84. At that time, the sprag 238 bears against thethumbwheel 84 under the biasing of the living hinge 239. When theshutter release 94 assumes the upward released position, a downwardlyextending toe 242 contacts the sprag 238 and pushes the sprag 238 intothe pivoted configuration as a result of the interference between aridged surface 244 on the sprag 238 and the toe 242. The toe 242 can beprovided as a protrusion of the front cover 42.

The tab 240 of the sprag 238 bears on the thumbwheel 84 and isconfigured so as to frictionally engage the thumbwheel 84 or to meshwith the thumbwheel 84. In the first case, illustrated in FIG. 35, thetab 240 is rounded off or flattened at an end adjoining the thumbwheel84 and the thumbwheel 84 has a surface or track 246 that receives thetab 240. The track 246 can be in the form of a groove. The surface ofthe track 246 can be roughened or otherwise finished or treated toimprove frictional engagement. In the second case, illustrated in FIGS.44-46, the thumbwheel 84 has a toothed rack 248 in place of the track246. The shape of the tab 240 is complementary to the teeth of the rack248.

Referring now particularly to FIGS. 6-7, 11-20, and 22-23, in aparticular embodiment of the invention, the rear housing part 30 isattached to the front housing part 28 by means of lugs 250 that engagematching catch portions 252 of the other part. The catch portions of thehousing part or parts are internal lugs and internal eye-tabs (flangeswith a hole for a respective lug). Preferred engineering plastics usedfor the shell 24 of the housing parts have sufficient flex to permitdeflection of the catch portions 252 past the lugs 250 during assembly.

After the film has been exposed, the camera 10 is presented to aprocessor for photofinishing. The knob 22 is pulled out. The rearhousing part 30 is pried open using a screwdriver or like tool (notillustrated). The rear cover 44 is then bent, as shown in FIG. 13 usinga screwdriver 251 or the like, at a line of weakness (not shown). Theresulting film door 256 is bent open and the film unit 18 is removed.

After the film unit 18 has been removed, the frame assembly 14 remainsin the front housing 12, held by retention features 254. The retentionfeatures 254 are releasable, but retain the camera frame assembly 14 inplace until deliberate efforts are undertaking to separate the cameraframe assembly 14 from the front housing part 28. The retention features254 can be releasable fasteners, including hook-and-eye tapes, orpealable adhesive layers or tapes.

In a particular embodiment of the invention, the frame assembly 14 isheld in place by interference between fasteners in the form of lugs 250of the front cover 42 and catch portions 252 of the filmless cameraframe assembly 14. The catch portions are outwardly extending externalledges of the covers. The lugs 250 can be the same ones use for theattachment of the rear housing part 30 to the front cover 42. This isnot preferred, because the positioning of the lugs 250 required for thetwo functions, causes the camera frame assembly 14 to be loosely grippedafter the rear cover 44 is removed. This can cause rattling and anincomplete closure between the front housing part 28 and the front cover42. In a preferred embodiment, a second set of lugs 250 is present onthe front housing part 28. The second set of lugs 250 b are forward ofthe first set of lugs 250 a used with the rear housing part 30. Thesecond set of lugs 250 b hold the camera frame assembly 14 tightly inplace against the front housing part 28. This allows better exclusion ofcontaminants from the front surface 258 of the taking lens.

The camera frame assembly 14 is removed from the front housing part 28for recycling by flexing the housing 12 part manually or using a pryingtool. These procedures can be provided by automatic machinery or,alternatively, manually using simple hand tools.

The invention has been described in detail with particular reference tocertain preferred embodiments thereof, but it will be understood thatvariations and modifications can be effected within the spirit and scopeof the invention.

What is claimed is:
 1. A pressure indicator comprising: an indicatorsupport surrounding an opening; an elastomer facing united with saidindicator support, said facing having a free region overlaying saidopening, said free region having an inner surface and an outer surface,said free region being deflectable by a relative pressure differentialbetween said inner and outer surfaces; wherein said indicator support isengineering plastic and said indicator support and said facing arecodiffused.
 2. The pressure indicator of claim 1 wherein said facing hasa supported region overlaying and united with said indicator support,said regions being continuous.
 3. The pressure indicator of claim 1further comprising a backup portion disposed interior to said opening,said backup portion being disposed in overlapping relation to saidopening.
 4. The pressure indicator of claim 3 wherein said free regionis deflected inward toward said backup portion when said inner surfaceis at a lower pressure than said outer surface.
 5. An underwater housinghaving an internal cavity sealed water-tightly from an externalenvironment, said housing comprising: a non-elastomer shell having aborder portion surrounding a passage; an elastomer facing having a freeregion overlaying said passage, said free region having an inner surfacein communication with said cavity and an outer surface in communicationwith the external environment, said free region being deflectable by arelative pressure differential between said inner and outer surfaces;wherein said facing is external to said shell.
 6. An underwater housinghaving an internal cavity sealed water-tightly from an externalenvironment, said housing comprising: a non-elastomer shell having aborder portion surrounding a passage; an elastomer facing having a freeregion overlaying said passage, said free region having an inner surfacein communication with said cavity and an outer surface in communicationwith the external environment, said free region being deflectable by arelative pressure differential between said inner and outer surfaces;wherein said shell is engineering plastic and said shell and said facingare codiffused.
 7. An underwater housing having an internal cavitysealed water-tightly from an external environment, said housingcomprising: a non-elastomer shell having a border portion surrounding apassage; an elastomer facing having a free region overlaying saidpassage, said free region having an inner surface in communication withsaid cavity and an outer surface in communication with the externalenvironment, said free region being deflectable by a relative pressuredifferential between said inner and outer surfaces; wherein said housinghas separable first and second housing parts, said first housing partincluding said border portion, said second housing part including abackup portion, said backup portion being disposed interior to saidpassage and in overlapping relation to said passage.
 8. The housing ofclaim 7 wherein said first housing part is a one-piece plastic casting.9. The housing of claim 7 wherein said inner and outer surfaces are in aflat configuration, a curved inward configuration, and curved outwardconfiguration, when said cavity is at a pressure that is the same as,lower than, and higher than said external environment, all respectively.10. The housing of claim 9 wherein said configurations of said outersurface are tactilely discenable.
 11. An underwater camera comprising ahousing defining an internal cavity, said housing sealing said internalcavity water-tightly from an external environment, said housingincluding: a non-elastomer shell having a border portion surrounding apassage; an elastomer facing having a free region overlaying saidpassage, said free region having an inner surface in communication withsaid cavity and an outer surface in communication with the externalenvironment, said free region being deflectable by a relative pressuredifferential between said inner and outer surfaces; and a camera frameassembly disposed in said internal cavity; wherein said housing hasseparable first and second housing parts, said first housing partincluding said border portion, said second housing part including abackup portion, said backup portion being disposed interior to saidpassage and in overlapping relation to said passage.
 12. The camera ofclaim 11 wherein said first housing part is a one-piece plastic casting.13. An underwater camera comprising a housing defining an internalcavity, said housing sealing said internal cavity water-tightly from anexternal environment, said housing including: a non-elastomer shellhaving a border portion surrounding a passage; an elastomer facinghaving a free region overlaying said passage, said free region having aninner surface in communication with said cavity and an outer surface incommunication with the external environment, said free region beingdeflectable by a relative pressure differential between said inner andouter surfaces; and a camera frame assembly disposed in said internalcavity; wherein said facing is external to said shell.